A pageview refers to the content opened in a browser window and is often used as a way of measuring website traffic. Each displayed web page counts as one pageview. Even if the web page consists of multiple frames, it is still counted as one document, equalling one pageview. See also: Hit

Perl

Practical Extraction and Reporting Language. Created by Larry Wall. Perl is a powerful programming language that has many uses, among them text processing, cgi scripting, network programming and database administration. Perl is available at no cost for all major operating systems, can be redistributed freely and has a large developer community.

PHP

PHP: Hypertext Preprocessor. PHP is a server-side scripting language, which means the PHP code is executed on the server, even though the PHP tags are embedded into HTML code. PHP is used to process form data, generate dynamic page content, or interact with databases. The databases supported include Oracle, InterBase, Informix, PostgreSQL and MySQL. PHP runs on many operating systems, among them Windows32, Macintosh, Unix and Linux.

Pixel

Picture Element. Electronically generated dot used to display an image on a computer monitor. An image is made up of thousands of individual pixels. The pixels are all the same size, but can vary in colour. An 8-bit colour monitor can display 256 pixels, while a 24-bit colour monitor can display more than 16 million. See also: Resolution

Plug-in

Module that extends the capabilities of a program. Browsers use plug-ins to perform various additional functions, for example to play streaming video over the internet. Third-party plug-ins are also developed for 3D and desktop publishing programs, adding extra features such as filters. See also: Quicktime

POP

Post Office Protocol. POP is a standard client/server protocol for receiving email, the latest version being POP3. Incoming email is received and held for the user by the web server. The next time the user checks the email account, the new email is downloaded from web server to the user's mailbox. Once the mail has been downloaded, it is deleted from the web server. The default port number for POP3 is 110. See also: IMAP, SMTP

Portal

A website which serves as a platform for internet users, usually centered on a main topic. Portals are characterized by offering their visitors many additional services, including search engines, chats, forums, news tickers, article archives, free email and weather forecasts. Examples of portals include larger internet providers (www.aol.com), online news services (www.cnn.com) and entertainment websites (www.mtv.com).

Proxy server

A proxy server manages the data flow between individual computers and a network, such as the Internet. For security reasons, the proxy server is often used together with a firewall and filters or blocks requests for certain sites or ports. Proxy servers can also help to speed up network traffic, caching frequently requested files to make overall performance more efficient. See also: Cache